离子束增强沉积掺杂氧化钒薄膜的最佳退火条件

用离子束增强沉积方法制备掺杂Ar和W的VO2多晶薄膜,明显改变了VO2薄膜的相变温度.试验发现,薄膜存在一个形成VO2结构的临界结晶温度,该温度随薄膜制备时沉积条件的不同而改变.选择适当的杂质和退火条件可以将VO2薄膜的相变温度降低到室温附近,获得较高室温电阻-温度系数的薄膜.     

钒和磷在土壤中的竞争吸附与迁移特性研究

应用批培养法和土柱法分别研究了钒和磷在两种美国耕地土壤(Sharkey重粘土和Cecil壤沙土)中的竞争吸附与迁移特征。结果表明，Sharkey重粘土对V表现出非常强的吸持能力，快速的吸持反应表现出了近似于平衡吸附的特征。加P对Sharkey土壤吸持V的能力没有明显的影响。Cecil壤沙土对V的吸附表现为快速的平衡吸附，不过其吸持能力要明显地小于Sharkey重粘土，而且，在前期被Cecil吸持的V会随培养时间的延长而部分被解吸出来。Sharkey对P的吸持能力略小于对V的吸持能力，且动态吸附特性比较明显。Cecil对P的吸附能力非常弱，V在Cecil沙壤土中的竞争吸附能力大于P。Cecil壤沙土对P和V，尤其是对V的吸持具有动态吸附的特征。     

Effect of Vanadium Content on VC Precipitation in PD3 Steel

In order to identify the affect of vanadium in pearlite transformation and the regularity of the precipitation, the effect of vanadium content on VC precipitation in PD3 steel has been studied by electrochemical extraction and TEM. The results show that the solid solubility limit of vanadium in the ferrite and Fe 3C is 0.09% and 0.23% respectively, that vanadium exist mainly as solid solution and a few VC particles are precipitated in disordered way in case of the vanadium content being below 0.21%, that VC particles are precipitated in excess of saturated solubility, and that a lot of VC particles are precipitated in disordered and "interphase precipitated" way in case of the vanadium content being above 0.21% and arrive at 0.33%.     

Growth performance and energetic metabolism of pacu, Piaractus mesopotamicus (Holmberg, 1887), fed diets supplemented with ammonium metavanadate

Vanadium compounds mimic most of the metabolic effects of insulin, suggesting that it might be useful to improve utilization of dietary carbohydrate. This work evaluated the effect of dietary ammonium metavanadate (H₄NO₃V) on the growth performance and energy metabolism of pacu, an omnivorous South America characin. Two hundred and eighty‐eight fish were distributed into four blocks according to the body weight (21.8±1.7, 28.5±2.0, 28.4±1.9, 35.7±1.9 g), stocked in 24 plastic tanks and fed twice daily with isonitrogenous and isoenergetic diets containing six levels of H₄NO₃V (0, 10, 50, 100, 300 and 1000 mg kg^?1) for 60 days. Increasing levels of dietary ammonium metavanadate did not improve growth (P>0.05), and the highest level of inclusion (1000 mg kg^?1) reduced performance (P<0.05). Blood glucose levels decreased (P<0.05) in fish fed 300 and 1000 mg kg^?1 H₄NO₃V, but no differences were observed in other blood metabolites. A slight increase in muscle lipid content was observed in fish fed a diet containing 300 mg kg^?1 H₄NO₃V. Based on the results of this study, there is no benefit in supplementing pacu diets with metavanadate.     

Petroleum Coke Circulating Fluidized Bed Combustion Product as a Sulfur Source for Alfalfa

Abstract: Petroleum coke circulating fluidized bed (CFB) combustion product is created when petroleum coke is combusted with limestone in a circulating fluidized bed boiler. The CFB product contains high concentrations of sulfur (S), nickel (Ni), and vanadium (V). Using it as a S source is encouraged, but little information is available related to plant responses and environmental impact. The CFB product was applied at rates of 0, 11, 33, and 110 kg S ha^?1 to two agricultural soils (Canfield silt loam and Wooster silt loam). Dry weight of alfalfa (Medicago sativa L.) and S in plant tissue was increased by the S treatments. Concentrations in alfalfa of V were increased but did not reach environmental concern levels. Concentrations in alfalfa of Ni were not increased. In the soils, only total S and plant available S were increased by these materials. No soil contamination problems were observed when CFB product was used as an S source.     

土壤中微量钒的分光光度测定方法研究 ——1 （2 吡啶偶氮） 2 萘酚-过氧化氢-十二烷基苯磺酸钠法

对钒(V)和1-(2-吡啶偶氮)-2-萘酚(PAN)-过氧化氢-十二烷基苯磺酸钠(SDBS)显色反应进行了试验,结果表明:在1 mol.L-1盐酸介质中,在SDBS存在下,钒与1-(2-吡啶偶氮)-萘酚和过氧化氢生成红色的多元络合物,络合物最大吸收波长为575 nm,表观摩尔吸收率为3.64×104L.mol-1.cm-1,钒的浓度在0.2～1.2μg.mL-1内符合比耳定律。络合物的组成比为n钒∶nPAN∶n过氧化氢=1∶1∶1。该方法用于土壤中钒的测定,测定值的相对偏差(n=20)均小于6%,回收率为100.4%～105.6%。     

蔬菜根际环境钒的形态变化及植物有效性

通过盆栽试验和Tessier连续提取法,研究了蔬菜根际和非根际土壤中钒的形态分布与植物有效性.结果表明,钒在根际和非根际土壤中主要以残渣态和铁锰氧化物结合态存在,钒的含量随其形态不同而变化:当土壤中钒添加量从25 mg·kg-1增加到200mg·kg-1时.根际土壤交换态钒的百分率增加了9.89%,碳酸盐结合态钒增加了9.38%,铁锰氧化物结合态钒增加了9.99%,残渣态钒的百分率下降了33.6%.土壤添加的钒最增加时,钒的迁移能力增强,使蔬菜的生物最显著降低,蔬菜对钒的吸收作用增强:钒添加量从0增至200mg·kg-1时,蔬菜鲜质量降低了41.65%,而蔬菜中85%以上的钒积累在根部.根际土壤中碳酸盐结合态钒含量对植物的根、茎叶中钒含量有显著影响,碳酸盐结合态钒与蔬菜鲜质量呈显著负相关.     

黄河口不同类型湿地土壤中钒和钴含量的空间分布特征

为研究不同植物群落下湿地土壤钒和钴含量的空间分布特征,利用ICP-MS对2009年5月在今黄河入海口北部的新生湿地区域依据不同植物群落设置9个采样区的土壤进行土壤钒和钴含量的分析。结果表明,尽管钒和钴含量在不同湿地土壤中差异较大,但二者在由陆向海方向潮滩湿地中的分布特征相似,且在水平方向上的变异均为中等变异。在垂直方向上,尽管钒和钴含量在不同类型湿地土壤中大多呈相似波动变化特征,但在同一类型湿地土壤中二者含量的变化趋势基本一致。相关分析表明,湿地土壤的钒钴含量在与铁锰、有机质、粘粒和粉粒含量均呈极显著正相关(P0.01),与砂粒含量呈极显著负相关(P0.01)。研究区表层湿地土壤的钒含量范围为72.77~118.40mg/kg,均值为93.06mg/kg;表层钴含量范围为8.94~16.91mg/kg,均值为12.54mg/kg。尽管研究区土壤的钒钴含量低于其全国背景值(112mg/kg和19mg/kg),但明显高于华北克拉通钒钴含量背景值(78mg/kg和12mg/kg)。黄河口新生湿地区土壤钒钴的富集系数分别为1.19和1.01,为弱程度的富集。研究表明,成土母质决定了湿地土壤中钒和钴含量的空间分布,土壤有机质含量、粒度组成和铁锰含量是影响二者空间分布的主导因素,而植被类型和潮汐对其分布亦具有重要影响。     

微生物还原五价钒的电子传递过程及其钒还原对藻类生长的影响

为探究微生物还原五价钒[V(Ⅴ)]的机理,从钒污染土壤中筛选出一株V(Ⅴ)还原菌,经鉴定为神户肠杆菌(Enterobacter kobei NC1-2),研究不同电子传递抑制剂和电子穿梭体对菌株NC1-2还原V(Ⅴ)的电子传递过程的影响,以及V(Ⅴ)微生物还原前后的毒性变化及其对藻类生长的影响。结果表明,当V(Ⅴ)初始浓度20 mg·L-1,培养3 d时菌株NC1-2对V(Ⅴ)的还原率为90.3%。扫描电镜(SEM)结果显示菌株表面附着无定形物质,结合能量散射X射线谱(EDS)分析证实无定形物质中含有钒元素;X射线光电子能谱(XPS)分析表明菌株NC1-2将V(Ⅴ)还原为V(Ⅳ)。电子传递抑制剂辣椒素、奎那克林和氯化铜能抑制菌株NC1-2对V(Ⅴ)的还原;核黄素作为电子穿梭体可缩短电子传递距离,促进胞外电子传递,有利于V(Ⅴ)的还原,进而加快菌株NC1-2对V(Ⅴ)的还原。V(Ⅴ)还原成V(Ⅳ)后毒性降低,减少了对小球藻Chlorella pyrenoidosa和斜生栅藻Scenedesmus obliquus的生长胁迫,两种藻生长96 h时的藻密度显著增加,且叶绿素a含量均有所提高,...     

Effects of vanadium supplementation on performance,some plasma metabolites and glucose metabolism in Mahabadi goat kids

This experiment was conducted to investigate the effects of vanadium (V) supplementation on performance, some plasma metabolites (cholesterol and triglycerides) and glucose metabolism in Mahabadi goat kids. Twenty‐eight male kids (15 ± 2 kg body weight) were fed for 14 weeks in a completely randomized design with four treatments. Treatments were supplemented with 0 (control), 1, 2, and 3 mg V as vanadyl sulfate/animal/daily. On day 70, an intravenous glucose tolerance test (IVGTT) was conducted. Dry matter intake did not change by V supplementation, but adding V quadraticaly improved feed efficiency (p = .03) and tended to increase average daily gain (Quadratic, p = .09). Blood metabolites were unaffected by V supplementation, except for concentration of glucose in plasma, which decreased linearly as supplemental V level increased (p = .02). Plasma glucose concentrations at 15, 30, 45 and 60 min after glucose infusion were decreased in a quadratic fashion in response to increasing supplemental V level (p < .01). The IVGTT indicated that the kids supplemented with 2 mg V had higher glucose clearance rate (K) and lower glucose half‐life (T_½; p < .05). Glucose area under the response curve from 0 to 60 min and 0 to 180 min after glucose infusion were decreased linearly (p = .04) by supplemental V. The results suggested that moderate supplementation of V may improve glucose utilization and feed efficiency in fattening kids.